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From:
Mark Kettenis <mark.kettenis@xs4all.nl>
Subject:
Re: scmi(4): add mbox transport and perf protocol
To:
Tobias Heider <tobias.heider@stusta.de>
Cc:
tech@openbsd.org, kettenis@openbsd.org, patrick@openbsd.org, landry@openbsd.org
Date:
Wed, 20 Nov 2024 23:16:29 +0100

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Thread
> Date: Wed, 20 Nov 2024 22:05:45 +0100
> From: Tobias Heider <tobias.heider@stusta.de>
> 
> On Tue, Nov 19, 2024 at 10:30:58PM GMT, Mark Kettenis wrote:
> > > Date: Tue, 19 Nov 2024 22:03:01 +0100
> > > From: Mark Kettenis <mark.kettenis@xs4all.nl>
> > > 
> > > > Date: Tue, 19 Nov 2024 14:20:12 +0100
> > > > From: Mark Kettenis <mark.kettenis@xs4all.nl>
> > > > 
> > > > > Date: Mon, 18 Nov 2024 01:01:11 +0100
> > > > > From: Tobias Heider <tobias.heider@stusta.de>
> > > > > 
> > > > > Here is the promised diff to get scmi for cpu frequency management
> > > > > working on the Snapdragon X Elite.  Roughly speaking this adds two
> > > > > big new features: mailbox transport and the scmi perf protocol.
> > > > > 
> > > > > Mailbox transport is very similar to smc which we already support.
> > > > > Messages are written to a shared memory region, instead of an SMC call we
> > > > > use a mailbox doorbell to notify the platform that our request is ready.
> > > > > On X Elites this is done using the CPUCP mailbox which we support via
> > > > > qccpucp(4). The attach function for the mbox transport is deferred to make
> > > > > sure our mailbox driver is available when we need it.
> > > > > There are a lot of possible optimization here, instead of polling we could
> > > > > use mailbox interrupts and for PERFORMANCE_LEVEL_GET we probably want to
> > > > > switch to using a fast channel at some point.
> > > > > 
> > > > > The perf protocol allows us to read and set the performance level of our
> > > > > performance domains. On the X Elite we have 3 domains, each spanning 4 cpu
> > > > > cores. This patch adds sensors to expose the current frequency and power
> > > > > consumption for each domain. It is a bit pointless since the level doesn't
> > > > > really change currently. Eventually we probably want to hook this up to
> > > > > cpu(4) to expose it to apm(8).
> > > > > 
> > > > > The output on my T14s looks like this:
> > > > > $ sysctl | grep scmi                                                   
> > > > > hw.sensors.scmi0.power0=0.22 W
> > > > > hw.sensors.scmi0.power1=0.29 W
> > > > > hw.sensors.scmi0.power2=0.31 W
> > > > > hw.sensors.scmi0.frequency0=2976000000.00 Hz
> > > > > hw.sensors.scmi0.frequency1=3417600000.00 Hz
> > > > > hw.sensors.scmi0.frequency2=3417600000.00 Hz
> > > > > 
> > > > > Test feedback and reviews welcome. I don't have a machine using scmi-smc or
> > > > > the clock protocol so I'd appreciate if someone could test those too.
> > > > 
> > > > A first drive-by review.  I need to test this on some hardware that
> > > > implements scmi-smc before I give an ok.  But it basically looks ok.
> > > 
> > > The rk3588 isn't happy with this.  I'll investigate...
> > 
> > Turns out to be a simple typo:
> > 
> > > > > +
> > > > > +	if (OF_is_compatible(faa->fa_node, "arm,scmi-scm")) {
> > > > > +		scmi_attach_smc(sc, faa);
> > 
> > Should be "arm,scmi-smc".
> 
> Here is a new version with all the feedback incorporated.
> Tests look good, works on X Elite, still work on Rockchip.
> 
> ok?

ok kettenis@

> diff a921796a245d04e3f9e9aeb92b328e0f67f5f697 1aba915c8fcaa5bd088fa5d0bf872ef48b3bd3eb
> commit - a921796a245d04e3f9e9aeb92b328e0f67f5f697
> commit + 1aba915c8fcaa5bd088fa5d0bf872ef48b3bd3eb
> blob - 5c567e567920508ecda4cc718168b85cc356898b
> blob + f7b1bf68a50fae33b840a317d0311e9d2143a31e
> --- sys/dev/fdt/scmi.c
> +++ sys/dev/fdt/scmi.c
> @@ -2,6 +2,7 @@
>  
>  /*
>   * Copyright (c) 2023 Mark Kettenis <kettenis@openbsd.org>
> + * Copyright (c) 2024 Tobias Heider <tobhe@openbsd.org>
>   *
>   * Permission to use, copy, modify, and distribute this software for any
>   * purpose with or without fee is hereby granted, provided that the above
> @@ -19,12 +20,16 @@
>  #include <sys/param.h>
>  #include <sys/device.h>
>  #include <sys/systm.h>
> +#include <sys/malloc.h>
> +#include <sys/sensors.h>
> +#include <sys/sysctl.h>
>  
>  #include <machine/bus.h>
>  #include <machine/fdt.h>
>  
>  #include <dev/ofw/openfirm.h>
>  #include <dev/ofw/ofw_clock.h>
> +#include <dev/ofw/ofw_misc.h>
>  #include <dev/ofw/fdt.h>
>  
>  #include <dev/fdt/pscivar.h>
> @@ -49,6 +54,7 @@ struct scmi_shmem {
>  
>  /* Protocols */
>  #define SCMI_BASE		0x10
> +#define SCMI_PERF		0x13
>  #define SCMI_CLOCK		0x14
>  
>  /* Common messages */
> @@ -64,6 +70,24 @@ struct scmi_shmem {
>  #define SCMI_CLOCK_CONFIG_SET			0x7
>  #define  SCMI_CLOCK_CONFIG_SET_ENABLE		(1 << 0)
>  
> +/* Performance management messages */
> +#define SCMI_PERF_DOMAIN_ATTRIBUTES		0x3
> +#define SCMI_PERF_DESCRIBE_LEVELS		0x4
> +#define SCMI_PERF_LEVEL_GET			0x8
> +
> +struct scmi_resp_perf_describe_levels_40 {
> +	uint16_t pl_nret;
> +	uint16_t pl_nrem;
> +	struct {
> +		uint32_t	pe_perf;
> +		uint32_t	pe_cost;
> +		uint16_t	pe_latency;
> +		uint16_t	pe_reserved;
> +		uint32_t	pe_ifreq;
> +		uint32_t	pe_lindex;
> +	} pl_entry[];
> +};
> +
>  static inline void
>  scmi_message_header(volatile struct scmi_shmem *shmem,
>      uint32_t protocol_id, uint32_t message_id)
> @@ -71,20 +95,58 @@ scmi_message_header(volatile struct scmi_shmem *shmem,
>  	shmem->message_header = (protocol_id << 10) | (message_id << 0);
>  }
>  
> +struct scmi_perf_level {
> +	uint32_t	pl_perf;
> +	uint32_t	pl_cost;
> +	uint32_t	pl_ifreq;
> +};
>  
> +struct scmi_perf_domain {
> +	size_t				pd_nlevels;
> +	struct scmi_perf_level		*pd_levels;
> +	int				pd_curlevel;
> +};
> +
>  struct scmi_softc {
>  	struct device			sc_dev;
>  	bus_space_tag_t			sc_iot;
> -	bus_space_handle_t		sc_ioh;
> -	volatile struct scmi_shmem	*sc_shmem;
> +	int				sc_node;
>  
> +	bus_space_handle_t		sc_ioh_tx;
> +	bus_space_handle_t		sc_ioh_rx;
> +	volatile struct scmi_shmem	*sc_shmem_tx;
> +	volatile struct scmi_shmem	*sc_shmem_rx;
> +
>  	uint32_t			sc_smc_id;
> +	struct mbox_channel		*sc_mc_tx;
> +	struct mbox_channel		*sc_mc_rx;
>  
> +	uint16_t			sc_ver_major;
> +	uint16_t			sc_ver_minor;
> +
> +	/* SCMI_CLOCK */
>  	struct clock_device		sc_cd;
> +
> +	/* SCMI_PERF */
> +	int				sc_perf_power_unit;
> +#define SCMI_POWER_UNIT_UW	0x2
> +#define SCMI_POWER_UNIT_MW	0x1
> +#define SCMI_POWER_UNIT_NONE	0x0
> +	size_t				sc_perf_ndomains;
> +	struct scmi_perf_domain		*sc_perf_domains;
> +
> +	struct ksensordev		sc_perf_sensordev;
> +	struct ksensordev		sc_perf_psensordev;
> +	struct ksensor			*sc_perf_fsensors;
> +	struct ksensor			*sc_perf_psensors;
> +
> +	int32_t				(*sc_command)(struct scmi_softc *);
>  };
>  
>  int	scmi_match(struct device *, void *, void *);
>  void	scmi_attach(struct device *, struct device *, void *);
> +int	scmi_attach_smc(struct scmi_softc *, struct fdt_attach_args *);
> +void	scmi_attach_mbox_deferred(struct device *);
>  
>  const struct cfattach scmi_ca = {
>  	sizeof(struct scmi_softc), scmi_match, scmi_attach
> @@ -96,22 +158,42 @@ struct cfdriver scmi_cd = {
>  
>  void	scmi_attach_proto(struct scmi_softc *, int);
>  void	scmi_attach_clock(struct scmi_softc *, int);
> -int32_t	scmi_command(struct scmi_softc *);
> +void	scmi_attach_perf(struct scmi_softc *, int);
>  
> +int32_t	scmi_smc_command(struct scmi_softc *);
> +int32_t	scmi_mbox_command(struct scmi_softc *);
> +
>  int
>  scmi_match(struct device *parent, void *match, void *aux)
>  {
>  	struct fdt_attach_args *faa = aux;
>  
> -	return OF_is_compatible(faa->fa_node, "arm,scmi-smc");
> +	return OF_is_compatible(faa->fa_node, "arm,scmi-smc") ||
> +	    OF_is_compatible(faa->fa_node, "arm,scmi");
>  }
>  
>  void
>  scmi_attach(struct device *parent, struct device *self, void *aux)
>  {
>  	struct scmi_softc *sc = (struct scmi_softc *)self;
> +	struct fdt_attach_args *faa = aux;
> +
> +	sc->sc_iot = faa->fa_iot;
> +	sc->sc_node = faa->fa_node;
> +
> +	if (OF_is_compatible(faa->fa_node, "arm,scmi-smc")) {
> +		scmi_attach_smc(sc, faa);
> +	} else if (OF_is_compatible(faa->fa_node, "arm,scmi")) {
> +		printf("\n");
> +		/* Defer because we need the mailbox driver attached first */
> +		config_defer(self, scmi_attach_mbox_deferred);
> +	}
> +}
> +
> +int
> +scmi_attach_smc(struct scmi_softc *sc, struct fdt_attach_args *faa)
> +{
>  	volatile struct scmi_shmem *shmem;
> -	struct fdt_attach_args *faa = aux;
>  	struct fdt_reg reg;
>  	int32_t status;
>  	uint32_t version;
> @@ -119,53 +201,142 @@ scmi_attach(struct device *parent, struct device *self
>  	void *node;
>  	int proto;
>  
> -	phandle = OF_getpropint(faa->fa_node, "shmem", 0);
> -	node = fdt_find_phandle(phandle);
> -	if (node == NULL || !fdt_is_compatible(node, "arm,scmi-shmem") ||
> -	    fdt_get_reg(node, 0, &reg)) {
> -		printf(": no shared memory\n");
> -		return;
> -	}
> -
>  	sc->sc_smc_id = OF_getpropint(faa->fa_node, "arm,smc-id", 0);
>  	if (sc->sc_smc_id == 0) {
>  		printf(": no SMC id\n");
> -		return;
> +		return -1;
>  	}
>  
> -	sc->sc_iot = faa->fa_iot;
> +	phandle = OF_getpropint(faa->fa_node, "shmem", 0);
> +	node = fdt_find_phandle(phandle);
> +	if (node == NULL || !fdt_is_compatible(node, "arm,scmi-shmem") ||
> +	    fdt_get_reg(node, 0, &reg)) {
> +		printf(": no shared memory\n");
> +		return -1;
> +	}
> +
>  	if (bus_space_map(sc->sc_iot, reg.addr,
> -	    reg.size, 0, &sc->sc_ioh)) {
> +	    reg.size, 0, &sc->sc_ioh_tx)) {
>  		printf(": can't map shared memory\n");
> -		return;
> +		return -1;
>  	}
> -	sc->sc_shmem = bus_space_vaddr(sc->sc_iot, sc->sc_ioh);
> -	shmem = sc->sc_shmem;
> +	sc->sc_shmem_tx = bus_space_vaddr(sc->sc_iot, sc->sc_ioh_tx);
> +	shmem = sc->sc_shmem_tx;
>  
> +	sc->sc_command = scmi_smc_command;
> +
>  	if ((shmem->channel_status & SCMI_CHANNEL_FREE) == 0) {
>  		printf(": channel busy\n");
> -		return;
> +		return -1;
>  	}
>  
>  	scmi_message_header(shmem, SCMI_BASE, SCMI_PROTOCOL_VERSION);
>  	shmem->length = sizeof(uint32_t);
> -	status = scmi_command(sc);
> +	status = sc->sc_command(sc);
>  	if (status != SCMI_SUCCESS) {
>  		printf(": protocol version command failed\n");
> -		return;
> +		return -1;
>  	}
>  
>  	version = shmem->message_payload[1];
> -	printf(": SCMI %d.%d\n", version >> 16, version & 0xffff);
> +	sc->sc_ver_major = version >> 16;
> +	sc->sc_ver_minor = version & 0xfffff;
> +	printf(": SCMI %d.%d\n", sc->sc_ver_major, sc->sc_ver_minor);
>  
>  	for (proto = OF_child(faa->fa_node); proto; proto = OF_peer(proto))
>  		scmi_attach_proto(sc, proto);
> +
> +	return 0;
>  }
>  
> +void
> +scmi_attach_mbox_deferred(struct device *self)
> +{
> +	struct scmi_softc *sc = (struct scmi_softc *)self;
> +	uint32_t *shmems;
> +	int32_t status;
> +	uint32_t version;
> +	struct fdt_reg reg;
> +	int len;
> +	void *node;
> +	int proto;
> +
> +	/* we only support the 2 mbox / 2 shmem case */
> +	len = OF_getproplen(sc->sc_node, "mboxes");
> +	if (len != 4 * sizeof(uint32_t)) {
> +		printf("%s: invalid number of mboxes\n", sc->sc_dev.dv_xname);
> +		return;
> +	}
> +
> +	len = OF_getproplen(sc->sc_node, "shmem");
> +	if (len != 2 * sizeof(uint32_t)) {
> +		printf("%s: invalid number of shmems\n", sc->sc_dev.dv_xname);
> +		return;
> +	}
> +
> +	shmems = malloc(len, M_DEVBUF, M_WAITOK);
> +	OF_getpropintarray(sc->sc_node, "shmem", shmems, len);
> +
> +	sc->sc_mc_tx = mbox_channel(sc->sc_node, "tx", NULL);
> +	if (sc->sc_mc_tx == NULL) {
> +		printf("%s: no tx mbox\n", sc->sc_dev.dv_xname);
> +		return;
> +	}
> +	sc->sc_mc_rx = mbox_channel(sc->sc_node, "rx", NULL);
> +	if (sc->sc_mc_rx == NULL) {
> +		printf("%s: no rx mbox\n", sc->sc_dev.dv_xname);
> +		return;
> +	}
> +
> +	node = fdt_find_phandle(shmems[0]);
> +	if (node == NULL || !fdt_is_compatible(node, "arm,scmi-shmem") ||
> +	    fdt_get_reg(node, 0, &reg)) {
> +		printf("%s: no shared memory\n", sc->sc_dev.dv_xname);
> +		return;
> +	}
> +	if (bus_space_map(sc->sc_iot, reg.addr, reg.size, 0, &sc->sc_ioh_tx)) {
> +		printf("%s: can't map shared memory\n", sc->sc_dev.dv_xname);
> +		return;
> +	}
> +	sc->sc_shmem_tx = bus_space_vaddr(sc->sc_iot, sc->sc_ioh_tx);
> +
> +	node = fdt_find_phandle(shmems[1]);
> +	if (node == NULL || !fdt_is_compatible(node, "arm,scmi-shmem") ||
> +	    fdt_get_reg(node, 0, &reg)) {
> +		printf("%s: no shared memory\n", sc->sc_dev.dv_xname);
> +		return;
> +	}
> +	if (bus_space_map(sc->sc_iot, reg.addr, reg.size, 0, &sc->sc_ioh_rx)) {
> +		printf("%s: can't map shared memory\n", sc->sc_dev.dv_xname);
> +		return;
> +	}
> +	sc->sc_shmem_rx = bus_space_vaddr(sc->sc_iot, sc->sc_ioh_rx);
> +
> +	sc->sc_command = scmi_mbox_command;
> +
> +	scmi_message_header(sc->sc_shmem_tx, SCMI_BASE, SCMI_PROTOCOL_VERSION);
> +	sc->sc_shmem_tx->length = sizeof(uint32_t);
> +	status = sc->sc_command(sc);
> +	if (status != SCMI_SUCCESS) {
> +		printf("%s: protocol version command failed\n",
> +		    sc->sc_dev.dv_xname);
> +		return;
> +	}
> +
> +	version = sc->sc_shmem_tx->message_payload[1];
> +	sc->sc_ver_major = version >> 16;
> +	sc->sc_ver_minor = version & 0xfffff;
> +	printf("%s: SCMI %d.%d\n", sc->sc_dev.dv_xname, sc->sc_ver_major,
> +	    sc->sc_ver_minor);
> +
> +	for (proto = OF_child(sc->sc_node); proto; proto = OF_peer(proto))
> +		scmi_attach_proto(sc, proto);
> +}
> +
>  int32_t
> -scmi_command(struct scmi_softc *sc)
> +scmi_smc_command(struct scmi_softc *sc)
>  {
> -	volatile struct scmi_shmem *shmem = sc->sc_shmem;
> +	volatile struct scmi_shmem *shmem = sc->sc_shmem_tx;
>  	int32_t status;
>  
>  	shmem->channel_status = 0;
> @@ -179,6 +350,32 @@ scmi_command(struct scmi_softc *sc)
>  	return shmem->message_payload[0];
>  }
>  
> +int32_t
> +scmi_mbox_command(struct scmi_softc *sc)
> +{
> +	volatile struct scmi_shmem *shmem = sc->sc_shmem_tx;
> +	int ret;
> +	int i;
> +
> +	shmem->channel_status = 0;
> +	ret = mbox_send(sc->sc_mc_tx, NULL, 0);
> +	if (ret != 0)
> +		return SCMI_NOT_SUPPORTED; 
> +
> +	/* XXX: poll for now */
> +	for (i = 0; i < 20; i++) {
> +		if (shmem->channel_status & SCMI_CHANNEL_FREE)
> +			break;
> +		delay(10);
> +	}
> +	if ((shmem->channel_status & SCMI_CHANNEL_ERROR))
> +		return SCMI_COMMS_ERROR;
> +	if ((shmem->channel_status & SCMI_CHANNEL_FREE) == 0)
> +		return SCMI_BUSY;
> +
> +	return shmem->message_payload[0];
> +}
> +
>  void
>  scmi_attach_proto(struct scmi_softc *sc, int node)
>  {
> @@ -186,6 +383,9 @@ scmi_attach_proto(struct scmi_softc *sc, int node)
>  	case SCMI_CLOCK:
>  		scmi_attach_clock(sc, node);
>  		break;
> +	case SCMI_PERF:
> +		scmi_attach_perf(sc, node);
> +		break;
>  	default:
>  		break;
>  	}
> @@ -200,13 +400,13 @@ int	scmi_clock_set_frequency(void *, uint32_t *, uint3
>  void
>  scmi_attach_clock(struct scmi_softc *sc, int node)
>  {
> -	volatile struct scmi_shmem *shmem = sc->sc_shmem;
> +	volatile struct scmi_shmem *shmem = sc->sc_shmem_tx;
>  	int32_t status;
>  	int nclocks;
>  
>  	scmi_message_header(shmem, SCMI_CLOCK, SCMI_PROTOCOL_ATTRIBUTES);
>  	shmem->length = sizeof(uint32_t);
> -	status = scmi_command(sc);
> +	status = sc->sc_command(sc);
>  	if (status != SCMI_SUCCESS)
>  		return;
>  
> @@ -226,28 +426,28 @@ void
>  scmi_clock_enable(void *cookie, uint32_t *cells, int on)
>  {
>  	struct scmi_softc *sc = cookie;
> -	volatile struct scmi_shmem *shmem = sc->sc_shmem;
> +	volatile struct scmi_shmem *shmem = sc->sc_shmem_tx;
>  	uint32_t idx = cells[0];
>  
>  	scmi_message_header(shmem, SCMI_CLOCK, SCMI_CLOCK_CONFIG_SET);
>  	shmem->length = 3 * sizeof(uint32_t);
>  	shmem->message_payload[0] = idx;
>  	shmem->message_payload[1] = on ? SCMI_CLOCK_CONFIG_SET_ENABLE : 0;
> -	scmi_command(sc);
> +	sc->sc_command(sc);
>  }
>  
>  uint32_t
>  scmi_clock_get_frequency(void *cookie, uint32_t *cells)
>  {
>  	struct scmi_softc *sc = cookie;
> -	volatile struct scmi_shmem *shmem = sc->sc_shmem;
> +	volatile struct scmi_shmem *shmem = sc->sc_shmem_tx;
>  	uint32_t idx = cells[0];
>  	int32_t status;
>  
>  	scmi_message_header(shmem, SCMI_CLOCK, SCMI_CLOCK_RATE_GET);
>  	shmem->length = 2 * sizeof(uint32_t);
>  	shmem->message_payload[0] = idx;
> -	status = scmi_command(sc);
> +	status = sc->sc_command(sc);
>  	if (status != SCMI_SUCCESS)
>  		return 0;
>  	if (shmem->message_payload[2] != 0)
> @@ -260,7 +460,7 @@ int
>  scmi_clock_set_frequency(void *cookie, uint32_t *cells, uint32_t freq)
>  {
>  	struct scmi_softc *sc = cookie;
> -	volatile struct scmi_shmem *shmem = sc->sc_shmem;
> +	volatile struct scmi_shmem *shmem = sc->sc_shmem_tx;
>  	uint32_t idx = cells[0];
>  	int32_t status;
>  
> @@ -270,9 +470,188 @@ scmi_clock_set_frequency(void *cookie, uint32_t *cells
>  	shmem->message_payload[1] = idx;
>  	shmem->message_payload[2] = freq;
>  	shmem->message_payload[3] = 0;
> -	status = scmi_command(sc);
> +	status = sc->sc_command(sc);
>  	if (status != SCMI_SUCCESS)
>  		return -1;
>  
>  	return 0;
>  }
> +
> +/* Performance management */
> +void	scmi_perf_descr_levels(struct scmi_softc *, int);
> +void	scmi_perf_refresh_sensor(void *);
> +
> +void
> +scmi_attach_perf(struct scmi_softc *sc, int node)
> +{
> +	volatile struct scmi_shmem *shmem = sc->sc_shmem_tx;
> +	int32_t status;
> +	uint32_t version;
> +	int i;
> +
> +	scmi_message_header(sc->sc_shmem_tx, SCMI_PERF, SCMI_PROTOCOL_VERSION);
> +	sc->sc_shmem_tx->length = sizeof(uint32_t);
> +	status = sc->sc_command(sc);
> +	if (status != SCMI_SUCCESS) {
> +		printf("%s: SCMI_PROTOCOL_VERSION failed\n",
> +		    sc->sc_dev.dv_xname);	
> +		return;
> +	}
> +
> +	version = shmem->message_payload[1];
> +	if (version != 0x40000) {
> +		printf("%s: invalid perf protocol version (0x%x != 0x4000)",
> +		    sc->sc_dev.dv_xname, version);	
> +		return;
> +	}
> +
> +	scmi_message_header(shmem, SCMI_PERF, SCMI_PROTOCOL_ATTRIBUTES);
> +	shmem->length = sizeof(uint32_t);
> +	status = sc->sc_command(sc);
> +	if (status != SCMI_SUCCESS) {
> +		printf("%s: SCMI_PROTOCOL_ATTRIBUTES failed\n",
> +		    sc->sc_dev.dv_xname);	
> +		return;
> +	}
> +
> +	sc->sc_perf_ndomains = shmem->message_payload[1] & 0xffff;
> +	sc->sc_perf_domains = malloc(sc->sc_perf_ndomains *
> +	    sizeof(struct scmi_perf_domain), M_DEVBUF, M_ZERO | M_WAITOK);
> +	sc->sc_perf_power_unit = (shmem->message_payload[1] >> 16) & 0x3;
> +
> +	strlcpy(sc->sc_perf_sensordev.xname, sc->sc_dev.dv_xname,
> +	    sizeof(sc->sc_perf_sensordev.xname));
> +	
> +	sc->sc_perf_fsensors =
> +	    malloc(sc->sc_perf_ndomains * sizeof(struct ksensor),
> +	    M_DEVBUF, M_ZERO | M_WAITOK);
> +	sc->sc_perf_psensors =
> +	    malloc(sc->sc_perf_ndomains * sizeof(struct ksensor),
> +	    M_DEVBUF, M_ZERO | M_WAITOK);
> +
> +	/* Add one frequency sensor per perf domain */
> +	for (i = 0; i < sc->sc_perf_ndomains; i++) {
> +		scmi_message_header(shmem, SCMI_PERF,
> +		    SCMI_PERF_DOMAIN_ATTRIBUTES);
> +		shmem->length = 2 * sizeof(uint32_t);
> +		shmem->message_payload[0] = i;
> +		status = sc->sc_command(sc);
> +		if (status != SCMI_SUCCESS) {
> +			printf("%s: SCMI_PERF_DOMAIN_ATTRIBUTES failed\n",
> +			    sc->sc_dev.dv_xname);	
> +			goto err;
> +		}
> +
> +		scmi_perf_descr_levels(sc, i);
> +
> +		sc->sc_perf_fsensors[i].type = SENSOR_FREQ;
> +		sensor_attach(&sc->sc_perf_sensordev, &sc->sc_perf_fsensors[i]);
> +		sc->sc_perf_psensors[i].type = SENSOR_WATTS;
> +		sensor_attach(&sc->sc_perf_sensordev, &sc->sc_perf_psensors[i]);
> +	}
> +	sensordev_install(&sc->sc_perf_sensordev);
> +	sensor_task_register(sc, scmi_perf_refresh_sensor, 1);
> +	return;
> +err:
> +	free(sc->sc_perf_fsensors, M_DEVBUF,
> +	    sc->sc_perf_ndomains * sizeof(struct ksensor));
> +	free(sc->sc_perf_psensors, M_DEVBUF,
> +	    sc->sc_perf_ndomains * sizeof(struct ksensor));
> +}
> +
> +void
> +scmi_perf_descr_levels(struct scmi_softc *sc, int domain)
> +{
> +	volatile struct scmi_shmem *shmem = sc->sc_shmem_tx;
> +	volatile struct scmi_resp_perf_describe_levels_40 *pl;
> +	struct scmi_perf_domain *pd = &sc->sc_perf_domains[domain];
> +	int status, i, idx;
> +
> +	idx = 0;
> +	do {
> +		scmi_message_header(shmem, SCMI_PERF,
> +		    SCMI_PERF_DESCRIBE_LEVELS);
> +		shmem->length = sizeof(uint32_t) * 3;
> +		shmem->message_payload[0] = domain;
> +		shmem->message_payload[1] = idx;
> +		status = sc->sc_command(sc);
> +		if (status != SCMI_SUCCESS) {
> +			printf("%s: SCMI_PERF_DESCRIBE_LEVELS failed\n",
> +			    sc->sc_dev.dv_xname);	
> +			return;
> +		}
> +
> +		pl = (struct scmi_resp_perf_describe_levels_40 *)
> +		    &shmem->message_payload[1];
> +
> +		if (pd->pd_levels == NULL) {
> +			pd->pd_nlevels = pl->pl_nret + pl->pl_nrem;
> +			pd->pd_levels = malloc(pd->pd_nlevels *
> +			    sizeof(struct scmi_perf_level),
> +			    M_DEVBUF, M_ZERO | M_WAITOK);
> +		}
> +
> +		for (i = 0; i < pl->pl_nret; i++) {
> +			pd->pd_levels[idx + i].pl_cost =
> +			    pl->pl_entry[i].pe_cost;
> +			pd->pd_levels[idx + i].pl_perf =
> +			    pl->pl_entry[i].pe_perf;
> +			pd->pd_levels[idx + i].pl_ifreq =
> +			    pl->pl_entry[i].pe_ifreq;
> +		}
> +		idx += pl->pl_nret;
> +	} while (pl->pl_nrem);
> +}
> +
> +void
> +scmi_perf_refresh_sensor(void *arg)
> +{
> +	struct scmi_softc *sc = arg;
> +	volatile struct scmi_shmem *shmem = sc->sc_shmem_tx;
> +	uint64_t power_cost;
> +	int32_t status;
> +	int level, i;
> +
> +	if (sc->sc_perf_domains == NULL)
> +		return;
> +
> +	for (i = 0; i < sc->sc_perf_ndomains; i++) {
> +		if (sc->sc_perf_domains[i].pd_levels == NULL)
> +			return;
> +
> +		scmi_message_header(shmem, SCMI_PERF,
> +		    SCMI_PERF_LEVEL_GET);
> +		shmem->length = sizeof(uint32_t) * 2;
> +		shmem->message_payload[0] = i;
> +		status = sc->sc_command(sc);
> +		if (status != SCMI_SUCCESS) {
> +			printf("%s: SCMI_PERF_LEVEL_GET failed\n",
> +			    sc->sc_dev.dv_xname);	
> +			return;
> +		}
> +
> +		level = shmem->message_payload[1];
> +		if (sc->sc_perf_fsensors == NULL ||
> +		    sc->sc_perf_psensors == NULL)
> +			return;
> +
> +		sc->sc_perf_domains[i].pd_curlevel = level;
> +		sc->sc_perf_fsensors[i].value =
> +		    (uint64_t)sc->sc_perf_domains[i].
> +		    pd_levels[level].pl_ifreq * 1000000000;
> +
> +		switch (sc->sc_perf_power_unit) {
> +		case SCMI_POWER_UNIT_UW:
> +			power_cost = (uint64_t)sc->sc_perf_domains[i].
> +			    pd_levels[level].pl_cost;
> +			break;
> +		case SCMI_POWER_UNIT_MW:
> +			power_cost = (uint64_t)sc->sc_perf_domains[i].
> +			    pd_levels[level].pl_cost * 1000;
> +			break;
> +		default:
> +			continue;
> +		}
> +		sc->sc_perf_psensors[i].value = power_cost;
> +	}
> +}
>